Maintaining control over a load being carried by an implement coupled to a loader is important to help maximize worksite productivity. For instance, without sufficient load control, dirt or debris being carried by a bucket coupled to a loader may spill out of the bucket, thereby necessitating rework; similarly, without sufficient load control, material stacked on a pallet being carried by a fork coupled to a loader may fall off the pallet, also necessitating rework. Maintaining control over the angle of an implement coupled to a loader contributes significantly to maintaining control of a load being carried by the implement. However, the angle of such an implement may vary along the range of travel of the implement due to the kinematics of the system carrying the implement and/or due to slight drifts in the positions of the hydraulic cylinders helping to support the implement. Accordingly, systems for correcting such angle variations are desirable.
U.S. Pat. No. 7,140,830 B2 to Berger et al. discloses an electronic control system for skid steer loader controls. Specifically, the Berger et al. system provides a complex variety of modes, features, and options for controlling implement position, including an automatic implement self-leveling feature. The automatic implement self-leveling feature includes a return-to-dig mode and a horizon referencing mode. However, these modes in the Berger et al. system each rely largely upon multiple position sensors for information about implement position.